JP4295526B2 - Optical semiconductor element storage package and optical semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical semiconductor element storage package for use in an optical semiconductor device, particularly an optical semiconductor element storage package used in an optical semiconductor device such as an optical transmission / reception module using an optical signal of 10 Gbps or more, and the like. The present invention relates to the used optical semiconductor device.
[0002]
[Prior art]
An example of an optical semiconductor device using an optical semiconductor element storage package for storing an optical semiconductor element such as an LD (laser diode) or PD (photodiode) conventionally used in the optical communication field. 3 (a) to (c). 3A is a cross-sectional view of the optical semiconductor device, FIG. 3B is a right side view showing the state viewed from the right side of FIG. 3A with the lid removed, and FIG. 3C is FIG. It is a left view which shows a mode seen from the left side.
[0003]
This conventional optical semiconductor device has a mounting portion for the optical semiconductor element S at the center of the upper surface, and a through hole 101b having a diameter of 0.5 to 2 mm formed from one main surface to the other main surface in the vicinity of the mounting portion. , A disc-shaped metal substrate 101 made of a metal such as an iron (Fe) -nickel (Ni) -cobalt (Co) alloy or an iron (Fe) -nickel (Ni) alloy, and the through hole 101b, and at least other Iron (which is fixed through the sealing material 102 so that the end on the main surface side protrudes from the through hole 101b is electrically connected to the electrode of the optical semiconductor element S. A metal terminal 103 made of a metal such as an Fe) -nickel (Ni) -cobalt (Co) alloy or an iron (Fe) -nickel (Ni) alloy, and an electrode mounted on the mounting portion. And an optical semiconductor element S electrically connected to the end on the main surface side. The external circuit board 105 having the linear wiring conductor 104 formed on the upper surface from one side to the opposite side is connected to the metal terminal 103 protruding to the other main surface side of the metal board 101 in parallel to the wiring conductor 104. It is attached so as to be joined.
[0004]
The metal terminal 103 is fixed to the through hole 101b of the metal substrate 101 through a sealing material 102 made of insulating glass containing lead as a main component, and the metal substrate 101 and the metal are fixed by the sealing material 102. The product terminal 103 is electrically insulated.
[0005]
The optical semiconductor element S is brazed and fixed to the metal substrate 101 with a low melting point brazing material such as gold (Au) -tin (Sn) having a melting point of 200 to 400 ° C., and the electrode of the optical semiconductor element S is bonded to the bonding wire. It is electrically connected to an end portion on one main surface side of the metal terminal 103 through 106.
[0006]
Further, on the main surface of the metal substrate 101, a first lid 107a made of Fe—Ni—Co alloy or the like is provided on the outer peripheral portion within a width of 1 mm from the outer peripheral end for the purpose of protecting the optical semiconductor element S. The optical fiber 108 is fixed by laser welding, seam welding, brazing, or the like, and is optically coupled to a portion facing the optical semiconductor element S so as to cover the first lid 107a. The lid 107 is attached by joining the second lid 107b made of Fe—Ni—Co alloy or the like, and an optical semiconductor device as a product is obtained.
[0007]
In this optical semiconductor device, for example, the optical semiconductor element S is optically excited by a drive signal supplied from an external electric circuit (not shown), and the excited light is transmitted through an optical isolator (not shown) for returning light. The optical fiber 108 is used for high-capacity optical communication and the like by being transferred to and from the optical fiber 108. The adaptation range is widely used within a transmission distance of 40 km or less and a transmission capacity of 2.5 Gbps (Giga bit per second) or less.
[0008]
In recent years, the demand for high-speed communication at a transmission distance of 40 km or less has increased rapidly, and research and development on high-speed and large-capacity transmission has been promoted. In particular, an optical semiconductor device such as an optical transmission device that transmits an optical signal in an optical communication device has been attracting attention, and an increase in the speed of a high-frequency signal is a problem for improving the transmission capacity. In addition, the high-frequency signal used in the conventional optical semiconductor device is 2.5 Gbps or less, but in recent years, a higher speed of 10 Gbps or more has been demanded.
[0009]
[Patent Document 1]
JP-A-8-130266
[0010]
[Problems to be solved by the invention]
However, when an optical semiconductor device in which an optical semiconductor element driven by a high frequency signal of about 10 Gbps is mounted on a conventional optical semiconductor element storage package, the propagation mode of the high frequency signal changes in the metal terminal, and As a result, the characteristic impedance of the metal terminal also changes, so that the optical semiconductor element becomes difficult to operate normally, and particularly, there is a problem that the transmission characteristic of a high-frequency signal of 10 Gbps or more is greatly deteriorated.
[0011]
This is because the portion of the metal terminal that protrudes from the through hole of the metal substrate to the other main surface side does not have a so-called coaxial structure, so if the frequency of the high-frequency signal transmitted by this metal terminal increases, This is due to a large shift in the propagation mode of the part that is not structured, and a significant change in the characteristic impedance. As a result, the reflection loss at the time of input / output of the high-frequency signal increases, and the optical semiconductor element This is because the operability deteriorates.
[0012]
That is, in the configuration of the conventional optical semiconductor element storage package, the propagation mode of the high-frequency signal in the metal substrate, the portion located inside the through hole of the metal terminal, and the wiring conductor formed in the external circuit substrate is TEM (Transverse Electro Magnetic) mode, on the other hand, the part that protrudes from the through hole of the metal substrate of the metal terminal, and the propagation mode of the part other than the junction with the wiring conductor of the external circuit board is TE (Transverse Electric) Mode. For this reason, as the high frequency signal is transmitted, the TEM mode-TE mode-TEM mode and the propagation mode change. As for the characteristic impedance, the inductive component is dominant in the portion of the metal terminal that protrudes from the through hole of the metal substrate and other than the junction with the wiring conductor of the external circuit board, and the characteristic impedance is abrupt. To be high. This is because the reflection loss of the high-frequency signal is increased.
[0013]
The present invention has been made in view of the problems in the conventional technology as described above, and its purpose is to propagate a high-frequency signal in the vicinity of the junction between the optical semiconductor element housing package and the external circuit board and the characteristics thereof. Impedance can be matched, and as a result, an optical semiconductor element package capable of obtaining good transmission characteristics even for a high-frequency signal of 10 Gbps or more and operating an optical semiconductor element normally, and an optical semiconductor device using the same It is to provide.
[0014]
  The optical semiconductor element storage package of the present invention is:An optical semiconductor storage package bonded to an external circuit board,Dielectric substrate and the dielectric substrateThe one end face of the dielectric substrate insideFrom the other end surface to the lower surface of the dielectric substrate, and the one end surface from the other end surface to the lower end of the dielectric substrate. And formed parallel to the first line conductor toward the side, The one end face sideAn end is electrically connected to an end on the other end surface side of the first line conductor via a through conductor,A region extending from the end connected to the through conductor to the other end surface side isFormed on the top surface of the external circuit boardBonded to the wiring conductorA second line conductor and a coplanar ground conductor layer formed on each side of the second line conductor on the lower surface of the dielectric substrate;To face the first line conductor inside the dielectric substrateFormed,The first line conductor is formed on the side opposite to the second line conductor.A grounding conductor layer; and a plurality of grounding through conductors that electrically connect the same-surface grounding conductor layer and the grounding conductor layer, respectively.The coplanar ground conductor layer is closer to the one end surface of the dielectric substrate than the connection portion,The first line conductorExists in the area opposite to.
  The joined body of the present invention comprises an external circuit board having a linear wiring conductor on the surface and a ground conductor provided on both sides of the wiring conductor, and an optical semiconductor element housing package to be joined to the external circuit board. Have. The optical semiconductor element storage package is:A dielectric substrate;The dielectric substrate is formed from one end surface to the other end surface side of the dielectric substrate, and the end portion on the one end surface side is electrically connected to the optical semiconductor element.The first line conductor is formed on the lower surface of the dielectric substrate in parallel with the first line conductor from the other end surface side toward the one end surface side., The one end face sideAn end portion is electrically connected to an end portion on the other end surface side of the first line conductor via a through conductor,AboveExternal circuit boardAboveA second line conductor joined in parallel to the wiring conductor, and the external circuit board formed on both sides of the second line conductor on the lower surface of the dielectric board, respectively.AboveA coplanar ground conductor layer joined to the ground conductor; andTo face the first line conductor inside the dielectric substrateBeen formed,The first line conductor is formed on the side opposite to the second line conductor.A grounding conductor layer, and a plurality of grounding through conductors that electrically connect the same-surface grounding conductor layer and the grounding conductor layer, respectively.It has.A connecting portion between the second line conductor and the through conductor is located on the external circuit board; andThe coplanar ground conductor layer is closer to one end surface of the dielectric substrate than the connection portion,The first line conductor and the external circuit board;Exist between.
[0015]
According to the optical semiconductor element storage package of the present invention, with the above-described configuration, the same-surface ground conductor layer, the ground conductor layer, and the plurality of grounding through conductors that connect them are formed between the optical semiconductor element and the external circuit board. Since it is provided so as to surround and cover the first line conductor and the second line conductor connecting the wiring conductor and the through conductor connecting these wiring conductors, it extends from the first line conductor to the wiring conductor of the external circuit board. All the high-frequency signal propagation modes become TEM modes, and changes in the propagation modes can be suppressed. In addition, a capacitive component is added to the first and second line conductors and the through conductors by the dielectric layer, the coplanar ground conductor layer, the ground conductor layer, and the plurality of ground through conductors, so that the characteristic impedance of these line conductors is increased. Can be suppressed, and the reflection loss of the high-frequency signal can be made extremely small. As a result, according to the optical semiconductor element housing package of the present invention, good transmission characteristics can be realized even for high-frequency signals of 10 Gbps or more, and the optical semiconductor element housed and accommodated can be operated normally.
[0016]
The optical semiconductor device of the present invention has the above structure.The one end surface of the dielectric substrateAn optical semiconductor element is mounted on the electrode, and an electrode of the optical semiconductor element is electrically connected to an end portion on the one end face side of the first line conductor to cover the optical semiconductor element and connect the optical fiber to the optical semiconductor. On one end face to optically couple to the elementLidIs attached.
  Moreover, the mounting structure of the optical semiconductor device of the present invention is the above bonded body.An optical semiconductor element is mounted on the one end face of the dielectric substrate, and an electrode of the optical semiconductor element is electrically connected to an end portion on the one end face side of the first line conductor to cover the optical semiconductor element. In addition, a lid is attached to the one end surface so as to optically couple the optical fiber to the optical semiconductor element.
[0017]
According to the optical semiconductor device of the present invention, with the above-described configuration, even if a high-frequency signal of 10 Gbps or higher, light is transmitted between an electrical signal transmitted through the wiring conductor of the external circuit board and an optical signal transmitted through the optical fiber. An optical semiconductor device capable of satisfactorily performing photoelectric conversion by the semiconductor element and capable of satisfactorily transmitting and processing a high-frequency signal of 10 Gbps or more can be obtained.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Next, an optical semiconductor element housing package of the present invention and an optical semiconductor device of the present invention using the same will be described in detail with reference to the accompanying drawings.
[0019]
FIG. 1A is a cross-sectional view showing an example of an embodiment of an optical semiconductor device in which an optical semiconductor element is mounted on an optical semiconductor element storage package of the present invention, and FIG. 1B and FIG. ) Is a side view showing the optical semiconductor device shown in FIG. 1A viewed from the right side in FIG. 1A with the lid removed, and the inside from the left side in FIG. 1A. It is side surface perspective drawing which shows a mode that it saw and seen.
[0020]
In these drawings, 1 is a dielectric substrate, 1a is a dielectric layer, 2 is a first line conductor, 3 is a second line conductor, 4 is a through conductor, 5 is a ground conductor layer on the same plane, and 6 is a ground conductor. Layer, 7 is a grounding through conductor, 8 is an external circuit board, 9 is a wiring conductor, 10 is a grounding conductor, and 12 is a lid, and these mainly constitute the package for housing an optical semiconductor element of the present invention. The optical semiconductor element storage package and the optical semiconductor element S constitute the optical semiconductor device of the present invention.
[0021]
The dielectric substrate 1 is formed by laminating a plurality of dielectric layers 1a, and has an optical semiconductor element S mounting portion on one end face thereof. Such a dielectric substrate 1 has a function of mounting the optical semiconductor element S and supporting a line conductor that electrically connects the optical semiconductor element S and the wiring conductor 9 of the external circuit board 8.
[0022]
The dielectric layer 1a constituting the dielectric substrate 1 is made of alumina (Al₂O₃) Ceramics, mullite (3Al₂O₃・ 2SiO₂) From ceramic materials such as ceramics, inorganic materials such as glass ceramics, or tetrafluoroethylene resin (polytetrafluoroethylene; PTFE), tetrafluoroethylene-ethylene copolymer resin (tetrafluoroethylene-ethylene copolymer resin; ETFE), fluororesin such as tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin; PFA), resin such as glass epoxy resin, polyphenylene ether resin, liquid crystal polyester, polyimide, etc. It consists of a system material, and its shape and dimensions (thickness, width, length, etc.) are appropriately set according to the frequency, characteristic impedance, etc. of the high-frequency signal used.
[0023]
Further, one main surface of the dielectric layer 1a is directed from one end surface of the dielectric substrate 1 to the other end surface side, and the main surface of the dielectric layer 1a which is the lower surface of the dielectric substrate 1 is disposed on the main surface of the dielectric substrate 1. A first line conductor 2 and a second line conductor 3 are attached in parallel to each other from the other end surface side to the one end surface side. The first line conductor 2 and the second line conductor 3 electrically connect the electrode of the optical semiconductor element S mounted on the mounting portion on one end face of the dielectric substrate 1 and the wiring conductor 9 of the external circuit board 8 described later. Connected.
[0024]
The first line conductor 2 and the second line conductor 3 are formed on a conductive layer made of a metal material suitable for high-frequency signal transmission, such as a Cu layer, a Mo—Mn layer, a W layer, or a Mo—Mn metallized layer. Ni plating layer and Au plating layer deposited, W metallized layer deposited Ni plating layer and Au plating layer, Cr-Cu alloy layer, Ni plating layer on Cr-Cu alloy layer and Ta plated with Au plating layer₂Ni-Cr alloy layer and Au plating layer deposited on N layer, Pt layer and Au plating layer deposited on Ti layer, or Pt layer and Au plating on Ni-Cr alloy layer It consists of a layer deposited, and is formed by thick film printing methods or various thin film forming methods, plating methods, etc., and its thickness and width are set according to the frequency and characteristic impedance of the transmitted high frequency signal The
[0025]
Further, the same surface ground conductor layer 5 is provided on both sides of the second line conductor 3 on the lower surface of the dielectric substrate 1, and the first line conductor 2 and the outside are provided on one main surface of the other dielectric layer 1a. The grounding conductor layer 6 facing the opposite side of the circuit board 8 is formed of the same material and the same method as the first line conductor 2 and the second line conductor 3.
[0026]
The intervals between the first line conductor 2 and the second line conductor 3 and the ground conductor layer 5 and the ground conductor layer 6 are set according to the frequency of the high-frequency signal to be transmitted, the characteristic impedance, and the like.
[0027]
In addition, the dielectric substrate 1 is electrically connected to an end portion of the first line conductor 2 on the other end surface side of the dielectric substrate 1 and an end portion on the one end surface side of the second line conductor 3 opposed thereto. The through conductors 4 are connected to each other, and the grounding through conductor 7 is formed to electrically connect the ground conductor layer 5 and the ground conductor layer 6 to the same plane. Such through conductors 4 and grounding through conductors 7 are provided, for example, by forming through-hole conductors or via-hole conductors in the dielectric layer 1a, or by embedding metal plates, metal bars, metal pipes, or the like.
[0028]
The dielectric substrate 1 in the optical semiconductor element housing package of the present invention is manufactured by the following method.
[0029]
For example, if the dielectric layer 1a is made of alumina ceramics, first prepare a green sheet of alumina ceramics to be the dielectric layer 1a, and punch it through a predetermined punching process using a punching method or the like. To do. Next, if the first line conductor 2, the second line conductor 3, the through conductor 4, the coplanar ground conductor layer 5, the ground conductor layer 6, and the ground through conductor 7 are made of W metallized, a plurality of sheets A W paste is printed on a predetermined surface of the dielectric layer 1a by screen printing or the like to form the first line conductor 2, the second line conductor 3, the coplanar ground conductor layer 5 and the ground conductor layer 6. At the same time, the through conductor 4 and the grounding through conductor 7 are formed by filling the inside of the through hole with W paste. Next, the dielectric layer 1a in which the first line conductor 2, the second line conductor 3, the through conductor 4, the coplanar ground conductor layer 5, the ground conductor layer 6, and the grounding through conductor 7 are formed at predetermined positions. Then, a plurality of layers are sequentially stacked and pressed to obtain a stacked body that becomes the dielectric substrate 1.
[0030]
One end surface of this laminate is a mounting portion for mounting the optical semiconductor element S, and the second line conductor 3 is exposed on the lower surface of the dielectric substrate 1 so as to be joined in parallel with the wiring conductor 9 of the external circuit substrate 8. It is formed to do.
[0031]
In this case, it is formed so that the end portion of the first line conductor 2 is exposed on one end surface of the laminated body where the dielectric substrate 1 is mounted. Also, W paste is printed and applied to one end surface of the stacked body so as to be electrically connected to the exposed end of the first line conductor 2, and the optical semiconductor element S to be mounted and the electric The end face electrodes to be connected may be printed and applied. These are fired at a temperature of about 1600 ° C., and finally, Ni plating and Au plating are performed on each W metallized surface exposed on the surface.
[0032]
The second line conductor 3 formed on the lower surface of the dielectric substrate 1 is joined and electrically connected in parallel to the linear wiring conductor 9 formed on the surface of the external circuit substrate 8. The external circuit board 8 is a support base for supporting the wiring conductor 9, and is formed by the same material and the same method as those for the dielectric layer 1a. The wiring conductor 9 is for electrically connecting the second line conductor 3 and the wiring conductor of the external electric circuit board (not shown), and the first line conductor 2 and the second line conductor 2 described above. The line conductor 3 is formed as a straight line conductor on the upper surface of the external circuit board 8 by the same material and the same method. Further, ground conductors 10 are formed on both sides of the wiring conductor 9 on the upper surface of the external circuit board 8 by the same material and the same method as the wiring conductor 9, respectively. The ground conductor 10 also has a function of shielding a high-frequency signal transmitted through the wiring conductor 9. The dielectric substrate 1 and the external circuit substrate 8 are joined in parallel with the second line conductor 3 and the wiring conductor 9, and the same-surface ground conductor layer 5 and the ground conductor 10 with a brazing material or the like. It is joined by.
[0033]
The optical semiconductor element storage package of the present invention is formed by laminating a plurality of dielectric layers 1a as described above, and a dielectric substrate 1 having an optical semiconductor element S mounting portion on one end surface, and a dielectric substrate A first line conductor formed on one main surface of the dielectric layer 1a in the substrate 1 from one end surface toward the other end surface side and having an end on one end surface side electrically connected to an electrode of the optical semiconductor element S 2 and formed on the lower surface of the dielectric substrate 1 from the other end surface side to the one end surface side, and its end portion is electrically connected to the end portion on the other end surface side of the first line conductor 2 via the through conductor 4. The second line conductor 3 connected in parallel to the linear wiring conductor 9 formed on the upper surface of the external circuit board 8 and the both sides of the second line conductor 3 on the lower surface of the dielectric substrate 1. And ground conductors 10 formed on both sides of the wiring conductor 9 of the external circuit board 8 respectively. The same ground contact conductor layer 5 and the ground conductor layer 6 formed on one main surface of the other dielectric layer 1a and facing the first line conductor 2 on the opposite side of the external circuit board 8 A plurality of grounding through conductors 7 that electrically connect the ground conductor layer 5 and the ground conductor layer 6 and the optical fiber 13 are held, the optical semiconductor element S mounted on the mounting portion is covered, and the optical fiber 13 is In an optical semiconductor element storage package comprising a lid body 12 attached to one end face of the dielectric substrate 1 so as to be optically coupled to the optical semiconductor element S, the second line conductor 3 and the through conductor 4 The connecting portion is located on the external circuit board 8 before the peripheral edge of the external circuit board 8, and on the end of the external circuit board 8, the first line conductor 2, the external circuit board 8, The same-surface ground conductor layer 5 is extended in the area where the is important.
[0034]
According to the package for housing a semiconductor element of the present invention, with the configuration as described above, the same-surface ground conductor layer 5 and the ground conductor layer 6 and the plurality of grounding through conductors 7 connecting them are connected to the optical semiconductor element S and the outside. Since the first line conductor 2 and the second line conductor 3 that connect the wiring conductor 9 of the circuit board 8 and the through-conductor 4 that connects these are provided so as to surround and cover, the first line conductor All the high-frequency signal propagation modes from 2 to the wiring conductor 9 of the external circuit board 8 become TEM modes, and changes in the propagation modes can be suppressed. Further, a capacitive component is added to the first line conductor 2, the second line conductor 3, and the through conductor 4 by the dielectric layer 1 a, the coplanar ground conductor layer 5, the ground conductor layer 6, and the plurality of grounding through conductors 7. As a result, a sudden change in characteristic impedance in these line conductors can be suppressed, and the reflection loss of the high-frequency signal can be extremely reduced. As a result, according to the optical semiconductor element housing package of the present invention, good transmission characteristics can be realized even for high-frequency signals of 10 Gbps or more, and the optical semiconductor element S mounted and accommodated can be operated normally.
[0035]
Then, the optical semiconductor element S is mounted on the mounting portion on one end face of the dielectric substrate 1, and the electrode of the optical semiconductor element S and the end of the first line conductor 2 are electrically connected by a connecting member 14 such as a bonding wire. Then, the ring-shaped metal plate 11 made of Fe-Ni-Co alloy or the like is fixed by brazing or the like so as to surround the mounting portion on the outer peripheral portion of one end surface, and the outer peripheral end of the metal plate 11 The first lid 12a made of Fe-Ni-Co alloy or the like is fixed to the outer peripheral portion within 1 mm from the end by YAG laser welding, seam welding, brazing, or the like for the purpose of protecting the optical semiconductor element S. The second lid 12b in which the optical fiber 13 and the optical isolator (not shown) for preventing return light are bonded to the outer periphery of the first lid 12a with a resin adhesive or the like is attached by YAG laser welding or the like. By joining, the optical half mounted on the mounting part The optical fiber 13 is attached to the lid 12 to the one end face of the dielectric substrate 1 so as to optically couple to the optical semiconductor element S covers the body element S, the optical semiconductor device of the present invention as a product.
[0036]
According to such an optical semiconductor device of the present invention, even a high-frequency signal of 10 Gbps or more is transmitted between an electrical signal transmitted through the wiring conductor 9 of the external circuit board 8 and an optical signal transmitted through the optical fiber 13. Opto-electrical conversion can be satisfactorily performed by the optical semiconductor element S, and an optical semiconductor device capable of satisfactorily transmitting and processing a high-frequency signal of 10 Gbps or more can be obtained.
[0037]
【Example】
Examples of the optical semiconductor element storage package of the present invention will be described below.
[0038]
A Ni plating layer is formed on the lower surface of a dielectric substrate made of alumina ceramic having a relative dielectric constant of 9.4 and having a thickness of 0.38 mm and laminated on a W metallization having a line width of 0.46 mm as a second line conductor. And a line conductor formed by depositing an Au plating layer. In addition, the same-surface ground conductor layer is formed on the lower surface of the dielectric substrate, and the Ni plating layer is formed on the W metallization on the W metallization with a spacing of 0.25 mm so that the characteristic impedance of the second line conductor is 50Ω on both sides of the second line conductor. And a conductor layer formed by depositing an Au plating layer.
[0039]
Next, the first line conductor is parallel to the main surface of the dielectric layer in the dielectric substrate with a distance of 1.14 mm from the second line conductor, and the end on the other end surface side of the dielectric substrate is A line conductor made of W metallization having a line width of 0.41 mm was formed so as to face the end of the second line conductor on one end face side of the dielectric substrate.
[0040]
Then, on the main surface of the other dielectric layer facing the first line conductor on the opposite side of the external circuit board, with a distance of 2.28 mm from the lower surface of the dielectric board on which the second line conductor is formed, A ground conductor layer was formed so as to face one line conductor and the same-surface ground conductor layer. A through conductor that connects the first line conductor and the second line conductor, and a plurality of grounding through conductors that connect the same-surface ground conductor layer and the ground conductor layer are each a circle having a cross-sectional diameter of 0.15 mm. In a shape, formed by W metallization, and a direction parallel to the first and second line conductors between the grounding through conductors in which a plurality of grounding through conductors are arranged along the first and second line conductors And the distance in the direction perpendicular to the first and second line conductors between the grounding through conductors positioned opposite to each other with the first and second line conductors interposed therebetween is 1.6 mm. This obtained the sample 1 which is an Example of this invention.
[0041]
On the other hand, the configuration of the comparative example was as follows. First, the metal substrate was cut into a disk shape having a thickness of 1 mm and a diameter of 5.6 mm. A circular through hole for hermetically sealing the metal terminal by punching was formed in the center of the metal substrate. Further, a Ni layer having a thickness of 2 μm and an Au layer having a thickness of 2 μm were sequentially deposited on the surface of the metal substrate by a plating method. And the metal terminal was inserted in the through-hole of the metal substrate, and it sealed and joined with the glass sealing material. Thereby, Sample 2 as a comparative example was obtained.
[0042]
About these sample 1 and sample 2, after mounting VCSEL (Vertical Cavity Surface Emitting Laser) which is an optical semiconductor element using an Au-Sn brazing material, a first line conductor and a bonding wire are used. Each was electrically connected to a metal terminal. On the other hand, an external circuit board made of polyimide resin having a relative dielectric constant of 4.1 and having a conductor pattern to be a wiring conductor and a ground conductor formed on the main surface by Cu plating, having a thickness of 1.6 mm × length 30 mm × width 15 mm via solder The second line conductor of sample 1 and the metal terminal of sample 2 were electrically connected to each other, the wiring conductor and the ground conductor were connected to a network analyzer using a wafer probe, and the reflection loss for the high-frequency signal was measured. . The result is shown in FIG.
[0043]
FIG. 2 is a graph showing the frequency characteristics of reflection loss in Sample 1 and Sample 2. The horizontal axis represents frequency (unit: GHz), and the vertical axis represents reflection loss (unit: dB). Of the characteristic curves, the solid line indicates the frequency characteristic of the reflection loss of the sample 1 and the broken line indicates the frequency characteristic of the reflection loss of the sample 2.
[0044]
From the results shown in FIG. 2, it can be seen that Sample 1 which is an embodiment of the present invention realizes a favorable frequency characteristic with a reflection loss of −15 dB or less in a frequency region up to 15 GHz. On the other hand, in the sample 2 of the comparative example, it can be seen that the reflection loss increases in the frequency region of 2.5 GHz or more, and the value exceeds −10 dB. In the sample 1 which is an example of the present invention, such a characteristic deterioration was not observed in the illustrated frequency range, and a good characteristic was obtained.
[0045]
Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. For example, in the example of the above embodiment, the transmission line for transmitting a high-frequency signal between the external circuit board 8 and the optical semiconductor element S is the wiring conductor 9, the first and second line conductors 2 and 3, and the through-hole. Although the transmission line is composed of one conductor line like the conductor 4, these may be a transmission line composed of a pair of conductor lines such as a differential transmission line.
[0046]
【The invention's effect】
According to the optical semiconductor element storage package of the present invention, with the above-described configuration, the same-surface ground conductor layer, the ground conductor layer, and the plurality of grounding through conductors that connect them are formed between the optical semiconductor element and the external circuit board. Since it is provided so as to surround and cover the first line conductor and the second line conductor connecting the wiring conductor and the through conductor connecting these wiring conductors, it extends from the first line conductor to the wiring conductor of the external circuit board. All the high-frequency signal propagation modes become TEM modes, and changes in the propagation modes can be suppressed. In addition, a capacitive component is added to the first and second line conductors and the through conductors by the dielectric layer, the coplanar ground conductor layer, the ground conductor layer, and the plurality of ground through conductors, so that the characteristic impedance of these line conductors is increased. Can be suppressed, and the reflection loss of the high-frequency signal can be made extremely small. As a result, according to the optical semiconductor element housing package of the present invention, good transmission characteristics can be realized even for high-frequency signals of 10 Gbps or more, and the optical semiconductor element housed and accommodated can be operated normally.
[0047]
In addition, according to the optical semiconductor device of the present invention, even if a high-frequency signal of 10 Gbps or higher, an optical semiconductor element transmits an optical signal between an electrical signal transmitted through a wiring conductor of an external circuit board and an optical signal transmitted through an optical fiber. An optical semiconductor device which can perform electrical conversion well and can transmit and process high-frequency signals of 10 Gbps or more can be obtained.
[0048]
As described above, according to the present invention, it is possible to match the propagation mode and characteristic impedance of a high-frequency signal in the vicinity of the junction between the optical semiconductor element housing package and the external circuit board. As a result, a high-frequency signal of 10 Gbps or higher With respect to the optical semiconductor device, it is possible to provide an optical semiconductor device package capable of obtaining good transmission characteristics and operating the optical semiconductor device normally, and an optical semiconductor device using the same.
[Brief description of the drawings]
FIG. 1A is a cross-sectional view showing an example of an embodiment of an optical semiconductor device in which an optical semiconductor element is mounted on an optical semiconductor element storage package of the present invention, and FIGS. FIG. 1A is a side view showing a state seen from the right side in FIG. 1A with the lid of the optical semiconductor device shown in FIG. 1A removed, and the inside is seen through from the left side in FIG. It is a side perspective figure which shows a mode.
FIG. 2 is a graph showing the relationship between frequency and reflection loss in an example and a comparative example of an optical semiconductor storage package of the present invention.
3A is a cross-sectional view showing an example of an optical semiconductor device using a conventional optical semiconductor storage package, and FIG. 3B is a view seen from the right side of FIG. (C) is a left side view showing a state viewed from the left side of (a).
[Explanation of symbols]
1. Dielectric substrate
1a ・ ・ ・ ・ ・ ・ Dielectric layer
2 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ First line conductor
3 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Second line conductor
4 .... Penetration conductor
5 ... Same grounded conductor layer
6 .... Grounding conductor layer
7 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Penetration conductor for grounding
8 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ External circuit board
9 ... Wiring conductor
10. ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Grounding conductor
12 ...
12a ・ ・ ・ ・ ・ ・ First cover
12b ......... the second lid
S ... Optical semiconductor device

Claims (4)

An optical semiconductor storage package bonded to an external circuit board,
A dielectric substrate ;
A first line conductor formed from the one end surface of the dielectric substrate toward the other end surface inside the dielectric substrate, the end of the one end surface being electrically connected to the optical semiconductor element ;
The dielectric substrate is formed on the lower surface of the dielectric substrate in parallel with the first line conductor from the other end surface side toward the one end surface side, and the end portion on the one end surface side is formed through the through conductor. is the other end surface side end portion and electrically connected to the line conductor, the region extending to the other end face side from the end connected to the through conductor, formed on the upper surface of the external circuit board wiring A second line conductor joined to the conductor;
A coplanar ground conductor layer formed on each side of the second line conductor on the lower surface of the dielectric substrate;
A grounding conductor layer formed so as to face the first line conductor inside the dielectric substrate, and formed on the opposite side of the second line conductor with respect to the first line conductor ;
A plurality of grounding through conductors that electrically connect the same-surface grounding conductor layer and the grounding conductor layer, respectively.
The coplanar ground conductor layer is present on the one end face side of the dielectric substrate with respect to the connection portion between the second line conductor and the through conductor and in a region facing the first line conductor. An optical semiconductor element storage package. An external circuit board having a linear wiring conductor on the surface and a ground conductor provided on both sides of the wiring conductor;
A package for housing an optical semiconductor element bonded to the external circuit board;
A joined body having
The optical semiconductor element storage package is:
A dielectric substrate;
A first line conductor formed from one end surface of the dielectric substrate toward the other end surface inside the dielectric substrate, the end of the one end surface being electrically connected to the optical semiconductor element ;
The dielectric substrate is formed on the lower surface of the dielectric substrate in parallel with the first line conductor from the other end surface side toward the one end surface side, and the end portion on the one end surface side is formed through the through conductor. is the other end surface side end portion and electrically connected to the line conductor, and a second line conductor which are joined in parallel to the wiring conductor of the external circuit board,
The respectively formed on both sides of the second line conductor of the lower surface of the dielectric substrate, and the same plane ground conductor layer is bonded to the grounding conductor of the external circuit board,
A grounding conductor layer formed on the opposite side of the second line conductor with respect to the first line conductor, the grounding conductor layer formed to face the first line conductor inside the dielectric substrate ;
A plurality of grounding through conductors that electrically connect the same-surface grounding conductor layer and the grounding conductor layer, respectively.
A connection portion between the second line conductor and the through conductor is located on the external circuit board, and the same-surface ground conductor layer is closer to one end surface of the dielectric substrate than the connection portion. , conjugate is present between the external circuit board and the first line conductor. An optical semiconductor element is mounted on the one end face of the dielectric substrate according to claim 1, and an electrode of the optical semiconductor element is electrically connected to an end portion on the one end face side of the first line conductor, An optical semiconductor device comprising a lid attached to the one end surface so as to cover the optical semiconductor element and to optically couple the optical fiber to the optical semiconductor element. An optical semiconductor element is mounted on the one end face of the dielectric substrate according to claim 2, and an electrode of the optical semiconductor element is electrically connected to an end portion on the one end face side of the first line conductor, A mounting structure for an optical semiconductor device, wherein a cover is attached to the one end surface so as to cover the optical semiconductor element and to optically couple the optical fiber to the optical semiconductor element.

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